SIEMENS, WERNER VON, a Ger man engineer and electrician; born in Lenthe, Hanover, Dec. 13, 1816. In 1834 he entered the Prussian artillery, and in 1844 was put in charge of the artillery workshops at Berlin. He early showed scientific tastes, and in 1841 took out his first patent for galvanic silver and gold plating. He was of peculiar service in developing the telegraphic system in Prussia, and discovered in this connec tion the valuable insulating property of gutta-percha for underground and sub marine cables. In 1849 he left the army, and shortly after the service of the state altogether, and devoted his energies to the construction of telegraphic and electrical apparatus of all kinds. The well-known firm of Siemens and Halske was estab lished in 1847 in Berlin; and subsequently branches were formed, chiefly under the management of the younger brothers of Werner Siemens, in St. Petersburg (1857), in London (1858), in Vienna (1858), and in Tiflis (1863). Besides de
vising numerous useful forms of galva nometers and other electrical instruments of precision, Werner Siemens was one of the discoverers of the principle of the self-acting dynamo. He also made val uable determinations of the electrical resistance of different substances, the resistance of a column of mercury one meter long and one square millimeter cross section at C. being known as the Siemens unit. His numerous scientific and technical papers, published in the "Proceedings" of the Berlin Academy (of which he became a member in 1874), in Poggendorff's "Annalen," in Dingler's "Polytechnische Journal," etc., were re published in collected form in 1881. In 1886 he gave 500,000 marks for the founding of an imperial institute of technology and physics; and in 1888 he was ennobled. He died in Berlin, Dec. 6, 1892.